The first feature film to be released in Technicolor was Becky Sharp in 1935; it had been preceded by a few live-action films in 1934. But the video above is of film prepared in 1922 (for reference this is before the first Laurel and Hardy movies).
The process uses Kodachrome film, and is explained at the Kodak A Thousand Words website.
"In these newly preserved tests, made in 1922 at the Paragon Studios in Fort Lee, New Jersey, actress Mae Murray appears almost translucent, her flesh a pale white that is reminiscent of perfectly sculpted marble, enhanced with touches of color to her lips, eyes, and hair..."The content of the video is largely irrelevant; it appears to be a sort of screen test using a silent movie actress. What is remarkable is the absolutely jaw-dropping color.